Crunch GP-1000.4 4-Channel Car Audio Amplifier

The Crunch GP-1000.4 is a four-channel Class A/B car audio amplifier designed to add external amplification to a speaker-based system. It provides four channels for front and rear speakers, with the flexibility to bridge channel pairs when a two-channel configuration is preferred. Its manufacturer-stated maximum output is 125 watts by four channels at 4 ohms, 250 watts by four channels at 2 ohms, or 500 watts by two channels bridged at 4 ohms.

This amplifier is suited to vehicle owners upgrading beyond head-unit power or integrating amplification with a factory radio. RCA low-level inputs support aftermarket source units, while speaker-level inputs provide an option for systems without RCA outputs. Input sensitivity is adjustable from 0.2 to 9 volts for matching the amplifier to the source signal.

The GP-1000.4 uses a Class A/B topology and a low-noise preamplifier circuit for full-range audio amplification. Its 10 Hz to 22 kHz frequency response supports use with component speakers, coaxial speakers, or appropriately configured subwoofer channels. Variable electronic crossovers help divide frequencies for the speakers connected to each channel pair.

Crunch equips the amplifier with SPEED-FET MOSFET output devices and a pulse-width-modulated power supply. The aluminum heat sink uses QTD, or Quick Thermal Dispersion, design to help manage operating heat. LED diagnostics provide power and protection status for monitoring overload or speaker-short conditions.

For system planning, the amplifier can operate in four-channel stereo, stereo plus bridged mono, dual stereo bridged, or dual bridged mono arrangements. It is stable down to 2 ohms per channel in unbridged use and requires a 4-ohm minimum load when bridged. This makes it a flexible choice for powering a conventional four-speaker system or for combining speaker channels with a bridged channel pair.

Key Features

• Four-Channel Class A/B Design: Powers front and rear speakers from one amplifier chassis.
• 2-Ohm Stereo Stability: Supports compatible 2-ohm loads on individual channels.
• 4-Ohm Bridged Operation: Lets each channel pair drive one compatible bridged load.
• Variable Electronic Crossovers: Helps tailor high-pass or low-pass frequency routing.
• RCA And Speaker-Level Inputs: Works with aftermarket radios or compatible factory-radio signals.
• QTD Aluminum Heat Sink: Helps disperse heat during normal amplifier operation.

Design & Installation

The GP-1000.4 has a black-and-red finish, an aluminum heat sink, nickel-plated brass connection terminals, and screw-down connectors. Its compact listed dimensions are 10 inches long, 8 inches wide, and 2.375 inches high, with a listed weight of 6.25 pounds. LED power and protection indicators are located on the amplifier for status monitoring.

Mount the amplifier securely in a ventilated location and do not install it upside down. The manufacturer specifies 4 AWG power and ground terminals, 12 AWG speaker terminals, and one 30A fuse; the power cable should be fused within 18 inches of the battery. Use RCA inputs when available, or connect the supplied high-level input harness to compatible factory speaker wiring when integrating with an OEM source unit.